Guide plate text

(The deep sea from the College of letter, chert-a of Bedded floor)
Geology: Sorachi-Yezo belt, lower empty Sorachi group and iwashimizu layer
Origin: Hokkaido in the shizunai-gun in the shizunai-Cho East static in-river with
Period: early Cretaceous from the late Triassic (2.2~1.2 million years ago) Description: chart is hard and dense sedimentary rocks are made of quartz crystal. Siliceous Radiolarian that plankton's (sio 2) in shells are deposited on the deep sea floor, was formed. There are a variety of colors such as white, gray, red, green, red by inclusion of iron oxide and manganese.

Chart deposited pelagic deep-sea reaching up to the trench about 100 million years due to movement of the oceanic plate and transported more than 1,000 kilometers, East Asia had frame in the early Cretaceous, which added to the continent.
Donated by South-gumi 2001.10.28 Samani, Hokkaido co., Ltd.
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Waseda University
Rock Stone

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